why don't you visit the doctor - Chiropractor.
For me, I gave birth to a baby last year, and I am visiting a doctor recently because the pain doesn't go away.
Although it's important, the doctor said EXERCISE is more important because we need to strengthen the muscle and have good sitting/standing...position.
I never do exercise, and the doctor said my muscle has very low flexibility, then in daily life, I always use the waist muscle and back (I don't aware of this) muscle instead. So, this makes the back pain worst and hard to go away.
Now, I force myself to do some stretching exercise every night.